The
end of the Han dynasty refers to the period from 189 to 220 CE, which roughly coincides with the reign of the
Han dynasty's last ruler,
Emperor Xian. During this period, the Han empire's institutions were destroyed by the warlord
Dong Zhuo, and fractured into regional regimes ruled by various warlords, some of whom were nobles and officials of the Han imperial court. Eventually, one of those warlords,
Cao Cao, was able to gradually reunify the empire, ostensibly under Emperor Xian's rule, but the empire was actually controlled by Cao Cao himself. Cao Cao's efforts to completely reunite the Han empire were rebuffed at the
Battle of Red Cliffs in 208 / 209, when his armies were defeated by the allied forces of
Sun Quan and
Liu Bei. The Han dynasty formally ended in 220 when Cao Cao's son and heir,
Cao Pi, pressured Emperor Xian into abdicating in his favour. Cao Pi became the emperor of a new state,
Cao Wei. A year later, in response to Cao Pi's usurpation of the Han throne, Liu Bei declared himself emperor of
Shu Han; and in 229, Sun Quan followed suit, declaring himself emperor of
Eastern Wu. The period from Emperor Xian's abdication in 220 to the partial reunification of China under the
Jin dynasty in 265 was known as the
Three Kingdoms era in Chinese history.